This invention relates to portable memory cards of the type containing an integrated circuit, and notably to the manufacture of such cards by an economical method.
The invention is applicable more precisely to prepayment cards, i.e. to cards to which is initially assigned a certain monetary value, the purchase of a card by the payment of this value making it possible to obtain certain services by successive cancellations or changes of state in memory elements assigned a unit value until the total value of the card is used up.
The prior art has already proposed, for the procurement of services, for example telephone calls, the use of an electronic-type memory card in which the memory is made up of elements which, as the card is used, are successively changed over from an intial state to a second state in an irreversible manner, the card becoming unusable when all the elements of its memory have gone over to the second state. As the card is not rechargeable, i.e. as the elements of its memory cannot be brought back to their initial state, it must be discarded. It is consequently important for its cost to be as low as possible in order to minimize the value of the consumable material.
There are known methods for the manufacture of electronic memory cards of standard format, according to which the integrated circuit is placed in a cavity which is provided in the card and which is then filled, totally or partially, with a coating material, and then closed by a thin sheet leaving visible only the metallic areas for the connection of the integrated circuit to a device exchanging data with the card. These methods generally involve a large number of delicate operations, such as: preparation of a cavity and of an integrated circuit module mounted on a suitable support, coating of the assembly and closing of the cavity, final pressing and routing of the card. Such methods are too costly to be applied to the manufacture of cards designed to be discarded after use.